/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2019, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#pragma once

#include "zconf.h"

#ifdef __cplusplus
extern "C"
{
#endif

#define ZLIB_VERSION "1.2.3"
#define ZLIB_VERNUM 0x1230

	/*
		 The 'zlib' compression library provides in-memory compression and
	  decompression functions, including integrity checks of the uncompressed
	  data.  This version of the library supports only one compression method
	  (deflation) but other algorithms will be added later and will have the
	  same stream interface.

		 Compression can be done in a single step if the buffers are large
	  enough (for example if an input file is mmap'ed), or can be done by
	  repeated calls of the compression function.  In the latter case, the
	  application must provide more input and/or consume the output
	  (providing more output space) before each call.

		 The compressed data format used by default by the in-memory functions
	  is the zlib format, which is a zlib wrapper documented in RFC 1950,
	  wrapped around a deflate stream, which is itself documented in RFC 1951.

		 The library also supports reading and writing files in gzip (.gz)
	  format with an interface similar to that of stdio using the functions that
	  start with "gz".  The gzip format is different from the zlib format.  gzip
	  is a gzip wrapper, documented in RFC 1952, wrapped around a deflate
	  stream.

		 This library can optionally read and write gzip streams in memory as
	  well.

		 The zlib format was designed to be compact and fast for use in memory
	  and on communications channels.  The gzip format was designed for single-
	  file compression on file systems, has a larger header than zlib to
	  maintain directory information, and uses a different, slower check method
	  than zlib.

		 The library does not install any signal handler. The decoder checks
	  the consistency of the compressed data, so the library should never
	  crash even in case of corrupted input.
	*/

	typedef voidpf(*alloc_func) OF((voidpf opaque, uInt items, uInt size));
	typedef void(*free_func) OF((voidpf opaque, voidpf address));

	struct internal_state;

	typedef struct z_stream_s
	{
		Bytef* next_in; /* next input byte */
		uInt avail_in; /* number of bytes available at next_in */
		uLong total_in; /* total nb of input bytes read so far */

		Bytef* next_out; /* next output byte should be put there */
		uInt avail_out; /* remaining free space at next_out */
		uLong total_out; /* total nb of bytes output so far */

		char* msg; /* last error message, nullptr if no error */
		struct internal_state FAR* state; /* not visible by applications */

		alloc_func zalloc; /* used to allocate the internal state */
		free_func zfree; /* used to free the internal state */
		voidpf opaque; /* private data object passed to zalloc and zfree */

		int data_type; /* best guess about the data type: binary or text */
		uLong adler; /* adler32 value of the uncompressed data */
		uLong reserved; /* reserved for future use */
	} z_stream;

	typedef z_stream FAR* z_streamp;

	/*
		 gzip header information passed to and from zlib routines.  See RFC 1952
	  for more details on the meanings of these fields.
	*/
	typedef struct gz_header_s
	{
		int text; /* true if compressed data believed to be text */
		uLong time; /* modification time */
		int xflags; /* extra flags (not used when writing a gzip file) */
		int os; /* operating system */
		Bytef* extra; /* pointer to extra field or Z_NULL if none */
		uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
		uInt extra_max; /* space at extra (only when reading header) */
		Bytef* name; /* pointer to zero-terminated file name or Z_NULL */
		uInt name_max; /* space at name (only when reading header) */
		Bytef* comment; /* pointer to zero-terminated comment or Z_NULL */
		uInt comm_max; /* space at comment (only when reading header) */
		int hcrc; /* true if there was or will be a header crc */
		int done; /* true when done reading gzip header (not used
					 when writing a gzip file) */
	} gz_header;

	typedef gz_header FAR* gz_headerp;

	/*
	   The application must update next_in and avail_in when avail_in has
	   dropped to zero. It must update next_out and avail_out when avail_out
	   has dropped to zero. The application must initialize zalloc, zfree and
	   opaque before calling the init function. All other fields are set by the
	   compression library and must not be updated by the application.

	   The opaque value provided by the application will be passed as the first
	   parameter for calls of zalloc and zfree. This can be useful for custom
	   memory management. The compression library attaches no meaning to the
	   opaque value.

	   zalloc must return Z_NULL if there is not enough memory for the object.
	   If zlib is used in a multi-threaded application, zalloc and zfree must be
	   thread safe.

	   On 16-bit systems, the functions zalloc and zfree must be able to
	   allocate exactly 65536 bytes, but will not be required to allocate more
	   than this if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On
	   MSDOS, pointers returned by zalloc for objects of exactly 65536 bytes
	   *must* have their offset normalized to zero. The default allocation
	   function provided by this library ensures this (see zutil.c). To reduce
	   memory requirements and avoid any allocation of 64K objects, at the
	   expense of compression ratio, compile the library with -DMAX_WBITS=14
	   (see zconf.h).

	   The fields total_in and total_out can be used for statistics or
	   progress reports. After compression, total_in holds the total size of
	   the uncompressed data and may be saved for use in the decompressor
	   (particularly if the decompressor wants to decompress everything in
	   a single step).
	*/

	/* constants */

#define Z_NO_FLUSH 0
#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
#define Z_SYNC_FLUSH 2
#define Z_FULL_FLUSH 3
#define Z_FINISH 4
#define Z_BLOCK 5
	/* Allowed flush values; see deflate() and inflate() below for details */

#define Z_OK 0
#define Z_STREAM_END 1
#define Z_NEED_DICT 2
#define Z_ERRNO (-1)
#define Z_STREAM_ERROR (-2)
#define Z_DATA_ERROR (-3)
#define Z_MEM_ERROR (-4)
#define Z_BUF_ERROR (-5)
#define Z_VERSION_ERROR (-6)
	/* Return codes for the compression/decompression functions. Negative
	 * values are errors, positive values are used for special but normal
	 * events.
	 */

#define Z_NO_COMPRESSION 0
#define Z_BEST_SPEED 1
#define Z_BEST_COMPRESSION 9
#define Z_DEFAULT_COMPRESSION (-1)
	/* compression levels */

#define Z_FILTERED 1
#define Z_HUFFMAN_ONLY 2
#define Z_RLE 3
#define Z_FIXED 4
#define Z_DEFAULT_STRATEGY 0
	/* compression strategy; see deflateInit2() below for details */

#define Z_BINARY 0
#define Z_TEXT 1
#define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
#define Z_UNKNOWN 2
	/* Possible values of the data_type field (though see inflate()) */

#define Z_DEFLATED 8
	/* The deflate compression method (the only one supported in this version)
	 */

#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */

#define zlib_version zlibVersion()
	/* for compatibility with versions < 1.0.2 */

	/* basic functions */

	ZEXTERN const char* ZEXPORT zlibVersion OF((void));
	/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
	   If the first character differs, the library code actually used is
	   not compatible with the zlib.h header file used by the application.
	   This check is automatically made by deflateInit and inflateInit.
	 */

	/*
	ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));

		 Initializes the internal stream state for compression. The fields
	   zalloc, zfree and opaque must be initialized before by the caller.
	   If zalloc and zfree are set to Z_NULL, deflateInit updates them to
	   use default allocation functions.

		 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and
	9: 1 gives best speed, 9 gives best compression, 0 gives no compression at
	   all (the input data is simply copied a block at a time).
	   Z_DEFAULT_COMPRESSION requests a default compromise between speed and
	   compression (currently equivalent to level 6).

		 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
	   enough memory, Z_STREAM_ERROR if level is not a valid compression level,
	   Z_VERSION_ERROR if the zlib library version (zlib_version) is
	incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
	set to null if there is no error message.  deflateInit does not perform any
	compression: this will be done by deflate().
	*/

	ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
	/*
		deflate compresses as much data as possible, and stops when the input
	  buffer becomes empty or the output buffer becomes full. It may introduce
	  some output latency (reading input without producing any output) except
	  when forced to flush.

		The detailed semantics are as follows. deflate performs one or both of
	  the following actions:

	  - Compress more input starting at next_in and update next_in and avail_in
		accordingly. If not all input can be processed (because there is not
		enough room in the output buffer), next_in and avail_in are updated and
		processing will resume at this point for the next call of deflate().

	  - Provide more output starting at next_out and update next_out and
	  avail_out accordingly. This action is forced if the parameter flush is non
	  zero. Forcing flush frequently degrades the compression ratio, so this
	  parameter should be set only when necessary (in interactive applications).
		Some output may be provided even if flush is not set.

	  Before the call of deflate(), the application should ensure that at least
	  one of the actions is possible, by providing more input and/or consuming
	  more output, and updating avail_in or avail_out accordingly; avail_out
	  should never be zero before the call. The application can consume the
	  compressed output when it wants, for example when the output buffer is
	  full (avail_out == 0), or after each call of deflate(). If deflate returns
	  Z_OK and with zero avail_out, it must be called again after making room in
	  the output buffer because there might be more output pending.

		Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate
	  to decide how much data to accumualte before producing output, in order to
	  maximize compression.

		If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
	  flushed to the output buffer and the output is aligned on a byte boundary,
	  so that the decompressor can get all input data available so far. (In
	  particular avail_in is zero after the call if enough output space has been
	  provided before the call.)  Flushing may degrade compression for some
	  compression algorithms and so it should be used only when necessary.

		If flush is set to Z_FULL_FLUSH, all output is flushed as with
	  Z_SYNC_FLUSH, and the compression state is reset so that decompression can
	  restart from this point if previous compressed data has been damaged or if
	  random access is desired. Using Z_FULL_FLUSH too often can seriously
	  degrade compression.

		If deflate returns with avail_out == 0, this function must be called
	  again with the same value of the flush parameter and more output space
	  (updated avail_out), until the flush is complete (deflate returns with
	  non-zero avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make
	  sure that avail_out is greater than six to avoid repeated flush markers
	  due to avail_out == 0 on return.

		If the parameter flush is set to Z_FINISH, pending input is processed,
	  pending output is flushed and deflate returns with Z_STREAM_END if there
	  was enough output space; if deflate returns with Z_OK, this function must
	  be called again with Z_FINISH and more output space (updated avail_out)
	  but no more input data, until it returns with Z_STREAM_END or an error.
	  After deflate has returned Z_STREAM_END, the only possible operations on
	  the stream are deflateReset or deflateEnd.

		Z_FINISH can be used immediately after deflateInit if all the
	  compression is to be done in a single step. In this case, avail_out must
	  be at least the value returned by deflateBound (see below). If deflate
	  does not return Z_STREAM_END, then it must be called again as described
	  above.

		deflate() sets strm->adler to the adler32 checksum of all input read
	  so far (that is, total_in bytes).

		deflate() may update strm->data_type if it can make a good guess about
	  the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
	  binary. This field is only for information purposes and does not affect
	  the compression algorithm in any manner.

		deflate() returns Z_OK if some progress has been made (more input
	  processed or more output produced), Z_STREAM_END if all input has been
	  consumed and all output has been produced (only when flush is set to
	  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for
	  example if next_in or next_out was nullptr), Z_BUF_ERROR if no progress is
	  possible (for example avail_in or avail_out was zero). Note that
	  Z_BUF_ERROR is not fatal, and deflate() can be called again with more
	  input and more output space to continue compressing.
	*/

	ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
	/*
		 All dynamically allocated data structures for this stream are freed.
	   This function discards any unprocessed input and does not flush any
	   pending output.

		 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
	   stream state was inconsistent, Z_DATA_ERROR if the stream was freed
	   prematurely (some input or output was discarded). In the error case,
	   msg may be set but then points to a static string (which must not be
	   deallocated).
	*/

	/*
	ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));

		 Initializes the internal stream state for decompression. The fields
	   next_in, avail_in, zalloc, zfree and opaque must be initialized before by
	   the caller. If next_in is not Z_NULL and avail_in is large enough (the
	exact value depends on the compression method), inflateInit determines the
	   compression method from the zlib header and allocates all data structures
	   accordingly; otherwise the allocation will be deferred to the first call
	of inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them
	to use default allocation functions.

		 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
	enough memory, Z_VERSION_ERROR if the zlib library version is incompatible
	with the version assumed by the caller.  msg is set to null if there is no
	error message. inflateInit does not perform any decompression apart from
	reading the zlib header if present: this will be done by inflate().  (So
	next_in and avail_in may be modified, but next_out and avail_out are
	unchanged.)
	*/

	ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
	/*
		inflate decompresses as much data as possible, and stops when the input
	  buffer becomes empty or the output buffer becomes full. It may introduce
	  some output latency (reading input without producing any output) except
	  when forced to flush.

	  The detailed semantics are as follows. inflate performs one or both of the
	  following actions:

	  - Decompress more input starting at next_in and update next_in and
	  avail_in accordingly. If not all input can be processed (because there is
	  not enough room in the output buffer), next_in is updated and processing
		will resume at this point for the next call of inflate().

	  - Provide more output starting at next_out and update next_out and
	  avail_out accordingly.  inflate() provides as much output as possible,
	  until there is no more input data or no more space in the output buffer
	  (see below about the flush parameter).

	  Before the call of inflate(), the application should ensure that at least
	  one of the actions is possible, by providing more input and/or consuming
	  more output, and updating the next_* and avail_* values accordingly.
	  The application can consume the uncompressed output when it wants, for
	  example when the output buffer is full (avail_out == 0), or after each
	  call of inflate(). If inflate returns Z_OK and with zero avail_out, it
	  must be called again after making room in the output buffer because there
	  might be more output pending.

		The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
	  Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
	  output as possible to the output buffer. Z_BLOCK requests that inflate()
	  stop if and when it gets to the next deflate block boundary. When decoding
	  the zlib or gzip format, this will cause inflate() to return immediately
	  after the header and before the first block. When doing a raw inflate,
	  inflate() will go ahead and process the first block, and will return when
	  it gets to the end of that block, or when it runs out of data.

		The Z_BLOCK option assists in appending to or combining deflate streams.
	  Also to assist in this, on return inflate() will set strm->data_type to
	  the number of unused bits in the last byte taken from strm->next_in, plus
	  64 if inflate() is currently decoding the last block in the deflate
	  stream, plus 128 if inflate() returned immediately after decoding an
	  end-of-block code or decoding the complete header up to just before the
	  first byte of the deflate stream. The end-of-block will not be indicated
	  until all of the uncompressed data from that block has been written to
	  strm->next_out.  The number of unused bits may in general be greater than
	  seven, except when bit 7 of data_type is set, in which case the number of
	  unused bits will be less than eight.

		inflate() should normally be called until it returns Z_STREAM_END or an
	  error. However if all decompression is to be performed in a single step
	  (a single call of inflate), the parameter flush should be set to
	  Z_FINISH. In this case all pending input is processed and all pending
	  output is flushed; avail_out must be large enough to hold all the
	  uncompressed data. (The size of the uncompressed data may have been saved
	  by the compressor for this purpose.) The next operation on this stream
	  must be inflateEnd to deallocate the decompression state. The use of
	  Z_FINISH is never required, but can be used to inform inflate that a
	  faster approach may be used for the single inflate() call.

		 In this implementation, inflate() always flushes as much output as
	  possible to the output buffer, and always uses the faster approach on the
	  first call. So the only effect of the flush parameter in this
	  implementation is on the return value of inflate(), as noted below, or
	  when it returns early because Z_BLOCK is used.

		 If a preset dictionary is needed after this call (see
	  inflateSetDictionary below), inflate sets strm->adler to the adler32
	  checksum of the dictionary chosen by the compressor and returns
	  Z_NEED_DICT; otherwise it sets strm->adler to the adler32 checksum of all
	  output produced so far (that is, total_out bytes) and returns Z_OK,
	  Z_STREAM_END or an error code as described below. At the end of the
	  stream, inflate() checks that its computed adler32 checksum is equal to
	  that saved by the compressor and returns Z_STREAM_END only if the checksum
	  is correct.

		inflate() will decompress and check either zlib-wrapped or gzip-wrapped
	  deflate data.  The header type is detected automatically.  Any information
	  contained in the gzip header is not retained, so applications that need
	  that information should instead use raw inflate, see inflateInit2() below,
	  or inflateBack() and perform their own processing of the gzip header and
	  trailer.

		inflate() returns Z_OK if some progress has been made (more input
	  processed or more output produced), Z_STREAM_END if the end of the
	  compressed data has been reached and all uncompressed output has been
	  produced, Z_NEED_DICT if a preset dictionary is needed at this point,
	  Z_DATA_ERROR if the input data was corrupted (input stream not conforming
	  to the zlib format or incorrect check value), Z_STREAM_ERROR if the stream
	  structure was inconsistent (for example if next_in or next_out was
	  nullptr), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if no
	  progress is possible or if there was not enough room in the output buffer
	  when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and inflate()
	  can be called again with more input and more output space to continue
	  decompressing. If Z_DATA_ERROR is returned, the application may then call
	  inflateSync() to look for a good compression block if a partial recovery
	  of the data is desired.
	*/

	ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
	/*
		 All dynamically allocated data structures for this stream are freed.
	   This function discards any unprocessed input and does not flush any
	   pending output.

		 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
	   was inconsistent. In the error case, msg may be set but then points to a
	   static string (which must not be deallocated).
	*/

	/* Advanced functions */

	/*
		The following functions are needed only in some special applications.
	*/

	/*
	ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
										 int  level,
										 int  method,
										 int  windowBits,
										 int  memLevel,
										 int  strategy));

		 This is another version of deflateInit with more compression options.
	The fields next_in, zalloc, zfree and opaque must be initialized before by
	   the caller.

		 The method parameter is the compression method. It must be Z_DEFLATED
	in this version of the library.

		 The windowBits parameter is the base two logarithm of the window size
	   (the size of the history buffer). It should be in the range 8..15 for
	this version of the library. Larger values of this parameter result in
	better compression at the expense of memory usage. The default value is 15
	if deflateInit is used instead.

		 windowBits can also be -8..-15 for raw deflate. In this case,
	-windowBits determines the window size. deflate() will then generate raw
	deflate data with no zlib header or trailer, and will not compute an adler32
	check value.

		 windowBits can also be greater than 15 for optional gzip encoding. Add
	   16 to windowBits to write a simple gzip header and trailer around the
	   compressed data instead of a zlib wrapper. The gzip header will have no
	   file name, no extra data, no comment, no modification time (set to zero),
	   no header crc, and the operating system will be set to 255 (unknown).  If
	a gzip stream is being written, strm->adler is a crc32 instead of an
	adler32.

		 The memLevel parameter specifies how much memory should be allocated
	   for the internal compression state. memLevel=1 uses minimum memory but
	   is slow and reduces compression ratio; memLevel=9 uses maximum memory
	   for optimal speed. The default value is 8. See zconf.h for total memory
	   usage as a function of windowBits and memLevel.

		 The strategy parameter is used to tune the compression algorithm. Use
	the value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced
	by a filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only
	(no string match), or Z_RLE to limit match distances to one (run-length
	   encoding). Filtered data consists mostly of small values with a somewhat
	   random distribution. In this case, the compression algorithm is tuned to
	   compress them better. The effect of Z_FILTERED is to force more Huffman
	   coding and less string matching; it is somewhat intermediate between
	   Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
	   Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
	strategy parameter only affects the compression ratio but not the
	correctness of the compressed output even if it is not set appropriately.
	Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
	decoder for special applications.

		  deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not
	enough memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
	   method). msg is set to null if there is no error message.  deflateInit2
	does not perform any compression: this will be done by deflate().
	*/

	ZEXTERN int ZEXPORT deflateSetDictionary
		OF((z_streamp strm, const Bytef* dictionary, uInt dictLength));
	/*
		 Initializes the compression dictionary from the given byte sequence
	   without producing any compressed output. This function must be called
	   immediately after deflateInit, deflateInit2 or deflateReset, before any
	   call of deflate. The compressor and decompressor must use exactly the
	   same dictionary (see inflateSetDictionary).

		 The dictionary should consist of strings (byte sequences) that are
	   likely to be encountered later in the data to be compressed, with the
	   most commonly used strings preferably put towards the end of the
	   dictionary. Using a dictionary is most useful when the data to be
	   compressed is short and can be predicted with good accuracy; the data can
	   then be compressed better than with the default empty dictionary.

		 Depending on the size of the compression data structures selected by
	   deflateInit or deflateInit2, a part of the dictionary may in effect be
	   discarded, for example if the dictionary is larger than the window size
	   in deflate or deflate2. Thus the strings most likely to be useful should
	   be put at the end of the dictionary, not at the front. In addition, the
	   current implementation of deflate will use at most the window size minus
	   262 bytes of the provided dictionary.

		 Upon return of this function, strm->adler is set to the adler32 value
	   of the dictionary; the decompressor may later use this value to determine
	   which dictionary has been used by the compressor. (The adler32 value
	   applies to the whole dictionary even if only a subset of the dictionary
	   is actually used by the compressor.) If a raw deflate was requested, then
	   the adler32 value is not computed and strm->adler is not set.

		 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
	   parameter is invalid (such as nullptr dictionary) or the stream state is
	   inconsistent (for example if deflate has already been called for this
	   stream or if the compression method is bsort). deflateSetDictionary does
	   not perform any compression: this will be done by deflate().
	*/

	ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, z_streamp source));
	/*
		 Sets the destination stream as a complete copy of the source stream.

		 This function can be useful when several compression strategies will be
	   tried, for example when there are several ways of pre-processing the
	   input data with a filter. The streams that will be discarded should then
	   be freed by calling deflateEnd.  Note that deflateCopy duplicates the
	   internal compression state which can be quite large, so this strategy is
	   slow and can consume lots of memory.

		 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
	   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
	   (such as zalloc being nullptr). msg is left unchanged in both source and
	   destination.
	*/

	ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
	/*
		 This function is equivalent to deflateEnd followed by deflateInit,
	   but does not free and reallocate all the internal compression state.
	   The stream will keep the same compression level and any other attributes
	   that may have been set by deflateInit2.

		  deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
	   stream state was inconsistent (such as zalloc or state being nullptr).
	*/

	ZEXTERN int ZEXPORT deflateParams
		OF((z_streamp strm, int level, int strategy));
	/*
		 Dynamically update the compression level and compression strategy.  The
	   interpretation of level and strategy is as in deflateInit2.  This can be
	   used to switch between compression and straight copy of the input data,
	   or to switch to a different kind of input data requiring a different
	   strategy. If the compression level is changed, the input available so far
	   is compressed with the old level (and may be flushed); the new level will
	   take effect only at the next call of deflate().

		 Before the call of deflateParams, the stream state must be set as for
	   a call of deflate(), since the currently available input may have to
	   be compressed and flushed. In particular, strm->avail_out must be
	   non-zero.

		 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
	   stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
	   if strm->avail_out was zero.
	*/

	ZEXTERN int ZEXPORT deflateTune
		OF((z_streamp strm, int good_length, int max_lazy, int nice_length,
			int max_chain));
	/*
		 Fine tune deflate's internal compression parameters.  This should only
	   be used by someone who understands the algorithm used by zlib's deflate
	   for searching for the best matching string, and even then only by the
	   most fanatic optimizer trying to squeeze out the last compressed bit for
	   their specific input data.  Read the deflate.c source code for the
	   meaning of the max_lazy, good_length, nice_length, and max_chain
	   parameters.

		 deflateTune() can be called after deflateInit() or deflateInit2(), and
	   returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
	 */

	ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, uLong sourceLen));
	/*
		 deflateBound() returns an upper bound on the compressed size after
	   deflation of sourceLen bytes.  It must be called after deflateInit()
	   or deflateInit2().  This would be used to allocate an output buffer
	   for deflation in a single pass, and so would be called before deflate().
	*/

	ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, int bits, int value));
	/*
		 deflatePrime() inserts bits in the deflate output stream.  The intent
	  is that this function is used to start off the deflate output with the
	  bits leftover from a previous deflate stream when appending to it.  As
	  such, this function can only be used for raw deflate, and must be used
	  before the first deflate() call after a deflateInit2() or deflateReset().
	  bits must be less than or equal to 16, and that many of the least
	  significant bits of value will be inserted in the output.

		  deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
	   stream state was inconsistent.
	*/

	ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, gz_headerp head));
	/*
		  deflateSetHeader() provides gzip header information for when a gzip
	   stream is requested by deflateInit2().  deflateSetHeader() may be called
	   after deflateInit2() or deflateReset() and before the first call of
	   deflate().  The text, time, os, extra field, name, and comment
	   information in the provided gz_header structure are written to the gzip
	   header (xflag is ignored -- the extra flags are set according to the
	   compression level).  The caller must assure that, if not Z_NULL, name and
	   comment are terminated with a zero byte, and that if extra is not Z_NULL,
	   that extra_len bytes are available there.  If hcrc is true, a gzip header
	   crc is included.  Note that the current versions of the command-line
	   version of gzip (up through version 1.3.x) do not support header crc's,
	   and will report that it is a "multi-part gzip file" and give up.

		  If deflateSetHeader is not used, the default gzip header has text
	   false, the time set to zero, and os set to 255, with no extra, name, or
	   comment fields.  The gzip header is returned to the default state by
	   deflateReset().

		  deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the
	   source stream state was inconsistent.
	*/

	/*
	ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
										 int  windowBits));

		 This is another version of inflateInit with an extra parameter. The
	   fields next_in, avail_in, zalloc, zfree and opaque must be initialized
	   before by the caller.

		 The windowBits parameter is the base two logarithm of the maximum
	window size (the size of the history buffer).  It should be in the
	range 8..15 for this version of the library. The default value is 15 if
	inflateInit is used instead. windowBits must be greater than or equal to the
	windowBits value provided to deflateInit2() while compressing, or it must be
	equal to 15 if deflateInit2() was not used. If a compressed stream with a
	larger window size is given as input, inflate() will return with the error
	code Z_DATA_ERROR instead of trying to allocate a larger window.

		 windowBits can also be -8..-15 for raw inflate. In this case,
	-windowBits determines the window size. inflate() will then process raw
	deflate data, not looking for a zlib or gzip header, not generating a check
	value, and not looking for any check values for comparison at the end of the
	stream. This is for use with other formats that use the deflate compressed
	data format such as zip.  Those formats provide their own check values. If a
	custom format is developed using the raw deflate format for compressed data,
	it is recommended that a check value such as an adler32 or a crc32 be
	applied to the uncompressed data as is done in the zlib, gzip, and zip
	formats.  For most applications, the zlib format should be used as is. Note
	that comments above on the use in deflateInit2() applies to the magnitude of
	windowBits.

		 windowBits can also be greater than 15 for optional gzip decoding. Add
	   32 to windowBits to enable zlib and gzip decoding with automatic header
	   detection, or add 16 to decode only the gzip format (the zlib format will
	   return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler
	is a crc32 instead of an adler32.

		 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not
	enough memory, Z_STREAM_ERROR if a parameter is invalid (such as a null
	strm). msg is set to null if there is no error message.  inflateInit2 does
	not perform any decompression apart from reading the zlib header if present:
	this will be done by inflate(). (So next_in and avail_in may be modified,
	but next_out and avail_out are unchanged.)
	*/

	ZEXTERN int ZEXPORT inflateSetDictionary
		OF((z_streamp strm, const Bytef* dictionary, uInt dictLength));
	/*
		 Initializes the decompression dictionary from the given uncompressed
	   byte sequence. This function must be called immediately after a call of
	   inflate, if that call returned Z_NEED_DICT. The dictionary chosen by the
	   compressor can be determined from the adler32 value returned by that call
	   of inflate. The compressor and decompressor must use exactly the same
	   dictionary (see deflateSetDictionary).  For raw inflate, this function
	   can be called immediately after inflateInit2() or inflateReset() and
	   before any call of inflate() to set the dictionary.  The application must
	   insure that the dictionary that was used for compression is provided.

		 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
	   parameter is invalid (such as nullptr dictionary) or the stream state is
	   inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
	   expected one (incorrect adler32 value). inflateSetDictionary does not
	   perform any decompression: this will be done by subsequent calls of
	   inflate().
	*/

	ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
	/*
		Skips invalid compressed data until a full flush point (see above the
	  description of deflate with Z_FULL_FLUSH) can be found, or until all
	  available input is skipped. No output is provided.

		inflateSync returns Z_OK if a full flush point has been found,
	  Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
	  has been found, or Z_STREAM_ERROR if the stream structure was
	  inconsistent. In the success case, the application may save the current
	  current value of total_in which indicates where valid compressed data was
	  found. In the error case, the application may repeatedly call inflateSync,
	  providing more input each time, until success or end of the input data.
	*/

	ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, z_streamp source));
	/*
		 Sets the destination stream as a complete copy of the source stream.

		 This function can be useful when randomly accessing a large stream. The
	   first pass through the stream can periodically record the inflate state,
	   allowing restarting inflate at those points when randomly accessing the
	   stream.

		 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
	   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
	   (such as zalloc being nullptr). msg is left unchanged in both source and
	   destination.
	*/

	ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
	/*
		 This function is equivalent to inflateEnd followed by inflateInit,
	   but does not free and reallocate all the internal decompression state.
	   The stream will keep attributes that may have been set by inflateInit2.

		  inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
	   stream state was inconsistent (such as zalloc or state being nullptr).
	*/

	ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, int bits, int value));
	/*
		 This function inserts bits in the inflate input stream.  The intent is
	  that this function is used to start inflating at a bit position in the
	  middle of a byte.  The provided bits will be used before any bytes are
	  used from next_in.  This function should only be used with raw inflate,
	  and should be used before the first inflate() call after inflateInit2() or
	  inflateReset().  bits must be less than or equal to 16, and that many of
	  the least significant bits of value will be inserted in the input.

		  inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
	   stream state was inconsistent.
	*/

	ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, gz_headerp head));
	/*
		  inflateGetHeader() requests that gzip header information be stored in
	   the provided gz_header structure.  inflateGetHeader() may be called after
	   inflateInit2() or inflateReset(), and before the first call of inflate().
	   As inflate() processes the gzip stream, head->done is zero until the
	   header is completed, at which time head->done is set to one.  If a zlib
	   stream is being decoded, then head->done is set to -1 to indicate that
	   there will be no gzip header information forthcoming.  Note that Z_BLOCK
	   can be used to force inflate() to return immediately after header
	   processing is complete and before any actual data is decompressed.

		  The text, time, xflags, and os fields are filled in with the gzip
	   header contents.  hcrc is set to true if there is a header CRC.  (The
	   header CRC was valid if done is set to one.)  If extra is not Z_NULL,
	   then extra_max contains the maximum number of bytes to write to extra.
	   Once done is true, extra_len contains the actual extra field length, and
	   extra contains the extra field, or that field truncated if extra_max is
	   less than extra_len. If name is not Z_NULL, then up to name_max
	   characters are written there, terminated with a zero unless the length is
	   greater than name_max.  If comment is not Z_NULL, then up to comm_max
	   characters are written there, terminated with a zero unless the length is
	   greater than comm_max.  When any of extra, name, or comment are not
	   Z_NULL and the respective field is not present in the header, then that
	   field is set to Z_NULL to signal its absence.  This allows the use of
	   deflateSetHeader() with the returned structure to duplicate the header.
	   However if those fields are set to allocated memory, then the application
	   will need to save those pointers elsewhere so that they can be eventually
	   freed.

		  If inflateGetHeader is not used, then the header information is simply
	   discarded.  The header is always checked for validity, including the
	   header CRC if present.  inflateReset() will reset the process to discard
	   the header information.  The application would need to call
	   inflateGetHeader() again to retrieve the header from the next gzip
	   stream.

		  inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the
	   source stream state was inconsistent.
	*/

	/*
	ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
											unsigned char FAR *window));

		 Initialize the internal stream state for decompression using
	inflateBack() calls.  The fields zalloc, zfree and opaque in strm must be
	initialized before the call.  If zalloc and zfree are Z_NULL, then the
	default library- derived memory allocation routines are used.  windowBits is
	the base two logarithm of the window size, in the range 8..15.  window is a
	caller supplied buffer of that size.  Except for special applications where
	it is assured that deflate was used with small window sizes, windowBits must
	be 15 and a 32K byte window must be supplied to be able to decompress
	general deflate streams.

		 See inflateBack() for the usage of these routines.

		 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
	   the paramaters are invalid, Z_MEM_ERROR if the internal state could not
	   be allocated, or Z_VERSION_ERROR if the version of the library does not
	   match the version of the header file.
	*/

	typedef unsigned(*in_func) OF((void FAR*, unsigned char FAR* FAR*));
	typedef int(*out_func) OF((void FAR*, unsigned char FAR*, unsigned));

	ZEXTERN int ZEXPORT inflateBack
		OF((z_streamp strm, in_func in, void FAR* in_desc, out_func out,
			void FAR* out_desc));
	/*
		 inflateBack() does a raw inflate with a single call using a call-back
	   interface for input and output.  This is more efficient than inflate()
	   for file i/o applications in that it avoids copying between the output
	   and the sliding window by simply making the window itself the output
	   buffer.  This function trusts the application to not change the output
	   buffer passed by the output function, at least until inflateBack()
	   returns.

		 inflateBackInit() must be called first to allocate the internal state
	   and to initialize the state with the user-provided window buffer.
	   inflateBack() may then be used multiple times to inflate a complete, raw
	   deflate stream with each call.  inflateBackEnd() is then called to free
	   the allocated state.

		 A raw deflate stream is one with no zlib or gzip header or trailer.
	   This routine would normally be used in a utility that reads zip or gzip
	   files and writes out uncompressed files.  The utility would decode the
	   header and process the trailer on its own, hence this routine expects
	   only the raw deflate stream to decompress.  This is different from the
	   normal behavior of inflate(), which expects either a zlib or gzip header
	   and trailer around the deflate stream.

		 inflateBack() uses two subroutines supplied by the caller that are then
	   called by inflateBack() for input and output.  inflateBack() calls those
	   routines until it reads a complete deflate stream and writes out all of
	   the uncompressed data, or until it encounters an error.  The function's
	   parameters and return types are defined above in the in_func and out_func
	   typedefs.  inflateBack() will call in(in_desc, &buf) which should return
	   the number of bytes of provided input, and a pointer to that input in
	   buf.  If there is no input available, in() must return zero--buf is
	   ignored in that case--and inflateBack() will return a buffer error.
	   inflateBack() will call out(out_desc, buf, len) to write the uncompressed
	   data buf[0..len-1].  out() should return zero on success, or non-zero on
	   failure.  If out() returns non-zero, inflateBack() will return with an
	   error.  Neither in() nor out() are permitted to change the contents of
	   the window provided to inflateBackInit(), which is also the buffer that
	   out() uses to write from. The length written by out() will be at most the
	   window size.  Any non-zero amount of input may be provided by in().

		 For convenience, inflateBack() can be provided input on the first call
	   by setting strm->next_in and strm->avail_in.  If that input is exhausted,
	   then in() will be called.  Therefore strm->next_in must be initialized
	   before calling inflateBack().  If strm->next_in is Z_NULL, then in() will
	   be called immediately for input.  If strm->next_in is not Z_NULL, then
	   strm->avail_in must also be initialized, and then if strm->avail_in is
	   not zero, input will initially be taken from strm->next_in[0 ..
	   strm->avail_in - 1].

		 The in_desc and out_desc parameters of inflateBack() is passed as the
	   first parameter of in() and out() respectively when they are called.
	   These descriptors can be optionally used to pass any information that the
	   caller- supplied in() and out() functions need to do their job.

		 On return, inflateBack() will set strm->next_in and strm->avail_in to
	   pass back any unused input that was provided by the last in() call.  The
	   return values of inflateBack() can be Z_STREAM_END on success,
	   Z_BUF_ERROR if in() or out() returned an error, Z_DATA_ERROR if there was
	   a format error in the deflate stream (in which case strm->msg is set to
	   indicate the nature of the error), or Z_STREAM_ERROR if the stream was
	   not properly initialized.  In the case of Z_BUF_ERROR, an input or output
	   error can be distinguished using strm->next_in which will be Z_NULL only
	   if in() returned an error.  If strm->next is not Z_NULL, then the
	   Z_BUF_ERROR was due to out() returning non-zero.  (in() will always be
	   called before out(), so strm->next_in is assured to be defined if out()
	   returns non-zero.)  Note that inflateBack() cannot return Z_OK.
	*/

	ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
	/*
		 All memory allocated by inflateBackInit() is freed.

		 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the
	   stream state was inconsistent.
	*/

	ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
	/* Return flags indicating compile-time options.

		Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
		 1.0: size of uInt
		 3.2: size of uLong
		 5.4: size of voidpf (pointer)
		 7.6: size of z_off_t

		Compiler, assembler, and debug options:
		 8: DEBUG
		 9: ASMV or ASMINF -- use ASM code
		 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
		 11: 0 (reserved)

		One-time table building (smaller code, but not thread-safe if true):
		 12: BUILDFIXED -- build static block decoding tables when needed
		 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
		 14,15: 0 (reserved)

		Library content (indicates missing functionality):
		 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
							  deflate code when not needed)
		 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't
	   detect and decode gzip streams (to avoid linking crc code) 18-19: 0
	   (reserved)

		Operation variations (changes in library functionality):
		 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
		 21: FASTEST -- deflate algorithm with only one, lowest compression
	   level 22,23: 0 (reserved)

		The sprintf variant used by gzprintf (zero is best):
		 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
		 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
		 26: 0 = returns value, 1 = void -- 1 means inferred string length
	   returned

		Remainder:
		 27-31: 0 (reserved)
	 */

	/* utility functions */

	/*
		 The following utility functions are implemented on top of the
	   basic stream-oriented functions. To simplify the interface, some
	   default options are assumed (compression level and memory usage,
	   standard memory allocation functions). The source code of these
	   utility functions can easily be modified if you need special options.
	*/

	ZEXTERN int ZEXPORT compress OF(
		(Bytef * dest, uLongf* destLen, const Bytef* source, uLong sourceLen));
	/*
		 Compresses the source buffer into the destination buffer.  sourceLen is
	   the byte length of the source buffer. Upon entry, destLen is the total
	   size of the destination buffer, which must be at least the value returned
	   by compressBound(sourceLen). Upon exit, destLen is the actual size of the
	   compressed buffer.
		 This function can be used to compress a whole file at once if the
	   input file is mmap'ed.
		 compress returns Z_OK if success, Z_MEM_ERROR if there was not
	   enough memory, Z_BUF_ERROR if there was not enough room in the output
	   buffer.
	*/

	ZEXTERN int ZEXPORT compress2
		OF((Bytef * dest, uLongf* destLen, const Bytef* source, uLong sourceLen,
			int level));
	/*
		 Compresses the source buffer into the destination buffer. The level
	   parameter has the same meaning as in deflateInit.  sourceLen is the byte
	   length of the source buffer. Upon entry, destLen is the total size of the
	   destination buffer, which must be at least the value returned by
	   compressBound(sourceLen). Upon exit, destLen is the actual size of the
	   compressed buffer.

		 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
	   memory, Z_BUF_ERROR if there was not enough room in the output buffer,
	   Z_STREAM_ERROR if the level parameter is invalid.
	*/

	ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
	/*
		 compressBound() returns an upper bound on the compressed size after
	   compress() or compress2() on sourceLen bytes.  It would be used before
	   a compress() or compress2() call to allocate the destination buffer.
	*/

	ZEXTERN int ZEXPORT uncompress OF(
		(Bytef * dest, uLongf* destLen, const Bytef* source, uLong sourceLen));
	/*
		 Decompresses the source buffer into the destination buffer.  sourceLen
	   is the byte length of the source buffer. Upon entry, destLen is the total
	   size of the destination buffer, which must be large enough to hold the
	   entire uncompressed data. (The size of the uncompressed data must have
	   been saved previously by the compressor and transmitted to the
	   decompressor by some mechanism outside the scope of this compression
	   library.) Upon exit, destLen is the actual size of the compressed buffer.
		 This function can be used to decompress a whole file at once if the
	   input file is mmap'ed.

		 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
	   enough memory, Z_BUF_ERROR if there was not enough room in the output
	   buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
	*/

	typedef voidp gzFile;

	ZEXTERN gzFile ZEXPORT gzopen OF((const char* path, const char* mode));
	/*
		 Opens a gzip (.gz) file for reading or writing. The mode parameter
	   is as in fopen ("rb" or "wb") but can also include a compression level
	   ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
	   Huffman only compression as in "wb1h", or 'R' for run-length encoding
	   as in "wb1R". (See the description of deflateInit2 for more information
	   about the strategy parameter.)

		 gzopen can be used to read a file which is not in gzip format; in this
	   case gzread will directly read from the file without decompression.

		 gzopen returns nullptr if the file could not be opened or if there was
	   insufficient memory to allocate the (de)compression state; errno
	   can be checked to distinguish the two cases (if errno is zero, the
	   zlib error is Z_MEM_ERROR).  */

	ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char* mode));
	/*
		 gzdopen() associates a gzFile with the file descriptor fd.  File
	   descriptors are obtained from calls like open, dup, creat, pipe or
	   fileno (in the file has been previously opened with fopen).
	   The mode parameter is as in gzopen.
		 The next call of gzclose on the returned gzFile will also close the
	   file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
	   descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
		 gzdopen returns nullptr if there was insufficient memory to allocate
	   the (de)compression state.
	*/

	ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
	/*
		 Dynamically update the compression level or strategy. See the
	   description of deflateInit2 for the meaning of these parameters.
		 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was
	   not opened for writing.
	*/

	ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
	/*
		 Reads the given number of uncompressed bytes from the compressed file.
	   If the input file was not in gzip format, gzread copies the given number
	   of bytes into the buffer.
		 gzread returns the number of uncompressed bytes actually read (0 for
	   end of file, -1 for error). */

	ZEXTERN int ZEXPORT gzwrite OF((gzFile file, voidpc buf, unsigned len));
	/*
		 Writes the given number of uncompressed bytes into the compressed file.
	   gzwrite returns the number of uncompressed bytes actually written
	   (0 in case of error).
	*/

	ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char* format, ...));
	/*
		 Converts, formats, and writes the args to the compressed file under
	   control of the format string, as in fprintf. gzprintf returns the number
	   of uncompressed bytes actually written (0 in case of error).  The number
	   of uncompressed bytes written is limited to 4095. The caller should
	   assure that this limit is not exceeded. If it is exceeded, then
	   gzprintf() will return return an error (0) with nothing written. In this
	   case, there may also be a buffer overflow with unpredictable
	   consequences, which is possible only if zlib was compiled with the
	   insecure functions sprintf() or vsprintf() because the secure snprintf()
	   or vsnprintf() functions were not available.
	*/

	ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char* s));
	/*
		  Writes the given null-terminated string to the compressed file,
	   excluding the terminating null character. gzputs returns the number of
	   characters written, or -1 in case of error.
	*/

	ZEXTERN char* ZEXPORT gzgets OF((gzFile file, char* buf, int len));
	/*
		  Reads bytes from the compressed file until len-1 characters are read,
	   or a newline character is read and transferred to buf, or an end-of-file
	   condition is encountered.  The string is then terminated with a null
	   character.
		  gzgets returns buf, or Z_NULL in case of error.
	*/

	ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
	/*
		  Writes c, converted to an unsigned char, into the compressed file.
	   gzputc returns the value that was written, or -1 in case of error.
	*/

	ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
	/*
		  Reads one byte from the compressed file. gzgetc returns this byte
	   or -1 in case of end of file or error.
	*/

	ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
	/*
		  Push one character back onto the stream to be read again later.
	   Only one character of push-back is allowed.  gzungetc() returns the
	   character pushed, or -1 on failure.  gzungetc() will fail if a
	   character has been pushed but not read yet, or if c is -1. The pushed
	   character will be discarded if the stream is repositioned with gzseek()
	   or gzrewind().
	*/

	ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
	/*
		 Flushes all pending output into the compressed file. The parameter
	   flush is as in the deflate() function. The return value is the zlib
	   error number (see function gzerror below). gzflush returns Z_OK if
	   the flush parameter is Z_FINISH and all output could be flushed.
		 gzflush should be called only when strictly necessary because it can
	   degrade compression.
	*/

	ZEXTERN z_off_t ZEXPORT gzseek
		OF((gzFile file, z_off_t offset, int whence));
	/*
		  Sets the starting position for the next gzread or gzwrite on the
	   given compressed file. The offset represents a number of bytes in the
	   uncompressed data stream. The whence parameter is defined as in lseek(2);
	   the value SEEK_END is not supported.
		 If the file is opened for reading, this function is emulated but can be
	   extremely slow. If the file is opened for writing, only forward seeks are
	   supported; gzseek then compresses a sequence of zeroes up to the new
	   starting position.

		  gzseek returns the resulting offset location as measured in bytes from
	   the beginning of the uncompressed stream, or -1 in case of error, in
	   particular if the file is opened for writing and the new starting
	   position would be before the current position.
	*/

	ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
	/*
		 Rewinds the given file. This function is supported only for reading.

	   gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
	*/

	ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
	/*
		 Returns the starting position for the next gzread or gzwrite on the
	   given compressed file. This position represents a number of bytes in the
	   uncompressed data stream.

	   gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
	*/

	ZEXTERN int ZEXPORT gzeof OF((gzFile file));
	/*
		 Returns 1 when EOF has previously been detected reading the given
	   input stream, otherwise zero.
	*/

	ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
	/*
		 Returns 1 if file is being read directly without decompression,
	   otherwise zero.
	*/

	ZEXTERN int ZEXPORT gzclose OF((gzFile file));
	/*
		 Flushes all pending output if necessary, closes the compressed file
	   and deallocates all the (de)compression state. The return value is the
	   zlib error number (see function gzerror below).
	*/

	ZEXTERN const char* ZEXPORT gzerror OF((gzFile file, int* errnum));
	/*
		 Returns the error message for the last error which occurred on the
	   given compressed file. errnum is set to zlib error number. If an
	   error occurred in the file system and not in the compression library,
	   errnum is set to Z_ERRNO and the application may consult errno
	   to get the exact error code.
	*/

	ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
	/*
		 Clears the error and end-of-file flags for file. This is analogous to
	   the clearerr() function in stdio. This is useful for continuing to read a
	   gzip file that is being written concurrently.
	*/

	/* checksum functions */

	/*
		 These functions are not related to compression but are exported
	   anyway because they might be useful in applications using the
	   compression library.
	*/

	ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef* buf, uInt len));
	/*
		 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
	   return the updated checksum. If buf is nullptr, this function returns
	   the required initial value for the checksum.
	   An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
	   much faster. Usage example:

		 uLong adler = adler32(0L, Z_NULL, 0);

		 while (read_buffer(buffer, length) != EOF) {
		   adler = adler32(adler, buffer, length);
		 }
		 if (adler != original_adler) error();
	*/

	ZEXTERN uLong ZEXPORT adler32_combine
		OF((uLong adler1, uLong adler2, z_off_t len2));
	/*
		 Combine two Adler-32 checksums into one.  For two sequences of bytes,
	   seq1 and seq2 with lengths len1 and len2, Adler-32 checksums were
	   calculated for each, adler1 and adler2.  adler32_combine() returns the
	   Adler-32 checksum of seq1 and seq2 concatenated, requiring only adler1,
	   adler2, and len2.
	*/

	ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef* buf, uInt len));
	/*
		 Update a running CRC-32 with the bytes buf[0..len-1] and return the
	   updated CRC-32. If buf is nullptr, this function returns the required
	   initial value for the for the crc. Pre- and post-conditioning (one's
	   complement) is performed within this function so it shouldn't be done by
	   the application. Usage example:

		 uLong crc = crc32(0L, Z_NULL, 0);

		 while (read_buffer(buffer, length) != EOF) {
		   crc = crc32(crc, buffer, length);
		 }
		 if (crc != original_crc) error();
	*/

	ZEXTERN uLong ZEXPORT crc32_combine
		OF((uLong crc1, uLong crc2, z_off_t len2));

	/*
		 Combine two CRC-32 check values into one.  For two sequences of bytes,
	   seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
	   calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
	   check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
	   len2.
	*/

	/* various hacks, don't look :) */

	/* deflateInit and inflateInit are macros to allow checking the zlib version
	 * and the compiler's view of z_stream:
	 */
	ZEXTERN int ZEXPORT deflateInit_
		OF((z_streamp strm, int level, const char* version, int stream_size));
	ZEXTERN int ZEXPORT inflateInit_
		OF((z_streamp strm, const char* version, int stream_size));
	ZEXTERN int ZEXPORT deflateInit2_
		OF((z_streamp strm, int level, int method, int windowBits, int memLevel,
			int strategy, const char* version, int stream_size));
	ZEXTERN int ZEXPORT inflateInit2_ OF(
		(z_streamp strm, int windowBits, const char* version, int stream_size));
	ZEXTERN int ZEXPORT inflateBackInit_
		OF((z_streamp strm, int windowBits, unsigned char FAR* window,
			const char* version, int stream_size));
#define deflateInit(strm, level) \
	deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
#define inflateInit(strm) inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
	deflateInit2_(                                                        \
		(strm), (level), (method), (windowBits), (memLevel), (strategy),  \
		ZLIB_VERSION, sizeof(z_stream))
#define inflateInit2(strm, windowBits) \
	inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
#define inflateBackInit(strm, windowBits, window) \
	inflateBackInit_(                             \
		(strm), (windowBits), (window), ZLIB_VERSION, sizeof(z_stream))

#if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
	struct internal_state
	{
		int dummy;
	}; /* hack for buggy compilers */
#endif

	ZEXTERN const char* ZEXPORT zError OF((int));
	ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
	ZEXTERN const uLongf* ZEXPORT get_crc_table OF((void));

#ifdef __cplusplus
}
#endif
